In 2020 FRAA changed their baseball bat standards per the following.
For Shetland, Pinto, Mustang, and Bronco Leagues the FRAA will allow only bats with the USA Baseball stamp up to a 2 5/8" barrel. Barrel sizes above 2 5/8" are not permitted, neither are any bats stamped with other standards (i.e. USSSA).
For Pony League, the bat standard shall remain the same which is either Drop -3 BBCOR or Drop -5 with 2 5/8" barrel containing the USA Baseball stamp.
If your child is on a tournament baseball team, the baseball bat rules may be different for any leagues or tournaments outside of the FRAA. Please consult your coach with any question regarding bats for these leagues and tournaments.
In 2018, the Baseball Bat standards changed. Here are a few links to the changes in bat standards:
https://usabat.com/about/
http://www.easton.com/new-youth-usa-bat-standard
http://protips.dickssportinggoods.com/sports-and-activities/baseball/2018-usa-baseball-youth-bat-standard-change
https://www.baberuthleague.org/bat-rules.aspx